Conflicts:
	src/slurmctld/job_mgr.c

Avoid hard-link/copy of script/environment files for job arrays. Use the
    master job record file for all tasks of the job array.
back port of commit 41eead64
bug 2220

Refactor logic to synchronize active bach jobs and their script/environment
    files, reducing overhead dramatically for large numbers of active jobs.
backport of commit 41eead64
bug 2220

If a job can never be started due to unsatisfied job dependencies, report
    the full original job dependency specification rather than the dependencies
    remaining to be satisfied (typically NULL).
bug 2197

in use.

Conflicts:
	src/slurmctld/proc_req.c

_slurm_rpc_complete_job_allocation.

This is a rewrite of 438365ec which didn't catch the job_ptr wasn't
in a lock so the memory issue could still of existed.  This hopefully fixes
all the spots the job_ptr wasn't in the lock.

Fixes bug 2146

This reverts commit 438365ec.

Bug 2261

15.08.5.

Bug 2243

Fix state machine to support corner cases when fan-in message for the next Fence appears before fan-out message completing the current Fence. This was observed on Orion as well as on containers environment in cases where Fences was light but the number of process was reasonably high.

Change the ordering of operations during fan-in. We will need this for the improved state machine. This changes are verified to work.

Optimization of fan-in collective stage. Sense parent by sending him a zero-sized message before sending him a junk of data. This helps to resolve cases where parent slurmstepd in collective haven't been yet bootstrapped.

Fix EIO: try to process message right in the place if possible instead of always switching to the AIO event handling.

This reverts commit 76098daf.

bug 2171

Decrease parallelism in job cancel request to prevent denial of service
    when cancelling huge numbers of jobs.
bug 2256